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If I were to take a blind stab where would a place to try stabbing be.

It has the upgraded fan software in it I yanked the controllers apart and verified with the numbers on the proms.

Since both circuits randomly are acting up with the random high pressure cutout and low oil flow could it be time for a slide valve rebuild and replace the unload and load solenoid while I'm at it. It's a 98 model chiller with a metric ton of run hours since it's in south texas and we average 106+ for day's on end during the summer.

This summer it ran perfect not a hiccup one other than a weak safety relief valve that dropped the charge on one circuit.

If I were to take a blind stab where would a place to try stabbing be.

It has the upgraded fan software in it I yanked the controllers apart and verified with the numbers on the proms.

Since both circuits randomly are acting up with the random high pressure cutout and low oil flow could it be time for a slide valve rebuild and replace the unload and load solenoid while I'm at it. It's a 98 model chiller with a metric ton of run hours since it's in south texas and we average 106+ for day's on end during the summer.

This summer it ran perfect not a hiccup one other than a weak safety relief valve that dropped the charge on one circuit.

I don't think that you have to take a blind stab. I think (as was said earlier) that you need to be there when it happens. If it's happening at a particular time of day or range of hours every time it happens, along with certain loading conditions not just on the evaporator but on the condenser, also, then be there when it takes place. Reconcile the cause with the conditions or you're just guessing.

Maybe he could install a fan cycle switch on each circuit temporarily to fire a set of fans and get a jump start on the chiller controls bringing the fans on . At least just to see if the alarms go away for a week or two. Sounds like that we have a theory of what's going on but this would throw that doubt out.

There's not a problem at all with doing just that, but I was concerned that one of the Trane guys who will remain unnamed would have a myocardial infarction and lose consciousness if anyone brought it up. Have a friend that posted once a few years back that he had done just what you said (on the advice of the local Trane factory office screw chiller guru, mind you) and the more outspoken Trane folks on the site basically tarred and feathered him. He don't come here no more.

Truth is, I like alot of the Trane gear. Them thangs can make a buttload of cold water when they're running. But they - like all others - have things about some of their designs that push the edge of common sense and good judgment about how to operate or control a piece of equipment. Historically, the Trane folks (not all, but most) have carried the "My stuff is better across the board than anyone else's" banner higher than the rest of the industry. It's hard to convince them that it's not hard to stop a Trane, but it can be aggravatin' as the dickens to get one (or keep one) running at times. They have good stuff and they have stuff that's not close to good, just like everyone else.

There's not a problem at all with doing just that, but I was concerned that one of the Trane guys who will remain unnamed would have a myocardial infarction and lose consciousness if anyone brought it up. Have a friend that posted once a few years back that he had done just what you said (on the advice of the local Trane factory office screw chiller guru, mind you) and the more outspoken Trane folks on the site basically tarred and feathered him. He don't come here no more.

Truth is, I like alot of the Trane gear. Them thangs can make a buttload of cold water when they're running. But they - like all others - have things about some of their designs that push the edge of common sense and good judgment about how to operate or control a piece of equipment. Historically, the Trane folks (not all, but most) have carried the "My stuff is better across the board than anyone else's" banner higher than the rest of the industry. It's hard to convince them that it's not hard to stop a Trane, but it can be aggravatin' as the dickens to get one (or keep one) running at times. They have good stuff and they have stuff that's not close to good, just like everyone else.

If you took the time to read all the posts on here concerning this issue (as well as the old ones ) you will find the answer to your problem .
This issue has enough posts and pages to fill new and old testaments and probably a copy of Gone With The Wind . I have answered so many times to guys with this problem and given them the answer and fix its not funny .
The thing that ticks me off is that no one bothers to use the search feature on here to research their problem , they just come on here with me "my chillers busted ..whats up with it " and expect an answer within .06microseconds ......it aint gonna happen ....
Pull up a chair grab a case of cold ones do the reading (carefully) and you will find your answer (its in print and plain to see) . Happy reading

The toy chest is officially full ... I got a new toy..... 2007 Aston Martin V8 Vantage and yes it still gives me goosebumps
You bend em" I"ll mend em" !!!!!!!
I"m not a service tech.. I"m a thermodynamic transfer analyst & strategic system sustainability specialist
In the new big shop , greasin', oilin' . tweakin' n shinin' !!

If you took the time to read all the posts on here concerning this issue (as well as the old ones ) you will find the answer to your problem .
This issue has enough posts and pages to fill new and old testaments and probably a copy of Gone With The Wind . I have answered so many times to guys with this problem and given them the answer and fix its not funny .
The thing that ticks me off is that no one bothers to use the search feature on here to research their problem , they just come on here with me "my chillers busted ..whats up with it " and expect an answer within .06microseconds ......it aint gonna happen ....
Pull up a chair grab a case of cold ones do the reading (carefully) and you will find your answer (its in print and plain to see) . Happy reading

Well did it work for your buddy? Trane does have its pro's and con's but like most things it has it's quirks that just happen and as we all know these are always the hardest to fix. I know people can't say too much about other people on the site because I'm sure good info would just dry up. I guess we all know that Graham is not coming to Texas to try to fix it so you have to do what you can whether it's a pressure switch or compressor overhaul.

This issue has enough posts and pages to fill new and old testaments and probably a copy of Gone With The Wind . I have answered so many times to guys with this problem and given them the answer and fix its not funny .

You're right in that this is probably the single most talked about service issue on this site. That also means that it's the single most prevalent issue among this site's constituents. That means that something is pushing the edge of sanity, especially when the most popular answer to the question is "are your condensers clean?". Not just clean, but spotless, immaculate, sterile, etc. We've heard all the adjectives. If I have to keep air-cooled condensers clean enough to perform surgery on, they're no good to me. We live in a world that has dirt in the air, and I'm taking care of a chiller, not building a watch.

As far as the other answers go, they sort of fall into the same category of "If it's that big a deal, why do they control it that way?". For all of their problems (and they are plentiful), I never saw a York YCAS have a problem with oil filter pressure drop due to excessive head pressure because one condenser fan crapped out or there was a nominally dirty condenser or the compressor started loaded or etc, etc. All because York simply started and stopped the fans off of head pressure, period. Mind you - I've never seen York or ex-York guys vehemently defend a poor way of doing something just because it's the York way, either, which is something that I can't say about the Trane folks in general.

I have several RTAA's that I take care of, and I like them. Over all, they're good chillers as air-cooled screws go. But face it - this issue gave Trane a black eye and has continued on because Trane wouldn't do anything about it. The attitude of Trane towards the "lifetime" oil filter on these chillers says more than I can ever say about their skewed view of reality on certain subjects. You know the one: it lasts the life of the chiller and should never need to be changed. If the circuit is that clean, why waste the money putting an oil filter on it in the first place? I've seen folks on this site with these questions get beat up severely about the oil filter thing by some Trane folks, only to be told later that if all else fails, maybe they do need to change the oil filter.

There is enough stuff on this subject to write a novel about, but there wouldn't be if it weren't so convoluted due to Trane's overall attitude about it. All have good and all have bad, no matter the name on the tag. And some things work just fine, even if I don't agree with the way it's done.

And I agree 100% with your assessment of the "non-use" of the search feature, by the way.......

double down on this one. although it is likely that the slide valve needs rebuilt, i prefer to verify the problem rather than fully trust a diagnostic code or description.

it could be that you are also experiencing a very high evaporator load, along with a sometimes sticking slide valve could cause high condensing pressures. sitting down to find out would allow that to be verified and then appropriate measures could be taken.

(side bar) as for Klove's discussion about clean coils...i don't think that 'sterile' is required, however, my personal viewpoint about 'keep your coils clean' versus 'modify the whole damn thing' is that keeping your coils clean is reasonable maintenance along with keeping a whole slew of problems from occuring along with less stress on the compressors and lower energy bills. i like the suggestion about modifying the wiring (temporarily) to find a fix or at least rule out the potential condenser fans as an issue. but permanently leaving the modification in place is asking for trouble. those who modify those units should not be able to ask for too much help in the future as certain control processes/procedures are assumed unless otherwise detailed.

YOU may be able to modify YOUR units very well and actually have them work much better in YOUR condition or climate than the factory has built and designed them, however, the factory (and those of us who are helping to diagnose problems from down the street to 12,500 miles away) has to design them for all conditions and climates as best as they can and sometimes salespersons sell them for conditions that the equipment is not best suited for....oh, and some bean counter and lawyer has final say in all equipment design for any manufacturer over 10 years old.

but to blanket-say that you SHOULD modify a unit in a certain way without proper engineering of the on-site conditions would be improper. to blanket-say that you SHOULDN'T modify a unit a certain way may also be improper, however, it is safer for the unit and the people operating it to leave it as the factory has decided (good or bad) to ship it.

Don't step on my favorite part of the Constitution just to point out your favorite part.

Political Correctness is forced on you because you have forgotten decency.

I'm fine with camping on it but just wanted to make sure I have several things to try and narrow it down. I've worked on mainly carrier chillers so this trane is a learning curve. But, personally so far I actually like trane commerical stuff more than the carrier. But they have 1 more RTAA that is working great. I'm not a parts changer so that's what's taking so long when I order parts if need be I want to be able to guarantee to my customer it's fixed. They are patient and understand it's a nasty little gremlin hiding it's just a matter of getting it cornered and terminated.

For diagnostic purposes lets say we put a fan cycling switch on it. Would a bank of 2 fans for each circuit probably be sufficient to rule one way or the other if it's a fan staging problem....?

On the RTAA's what involved with slide valve rebuilding. As far as parts needed and basic procedure. Once the end plate is pulled off of the compressor it's all right there I'm guessing. I have looked everywhere and cannot find a "trane screw rebuild/service manual"

Thanks for all of the help and suggestions it has at lease helped me get a good idea on what's happening to with it.

It doesnt seem likely both compressors have slide valve issues, though not impossible , sounds like fan staging to me, You need to there with gauges on , checking display transducers, pressures , temps to display ,remember you won`t have much time, A bit off subject but I had a carrier 30gx with oil fault that was driving me crazy , took me a few days to catch processor scrambling the oil pressures , scrolling like a maniac prodialog with gauges on, was a tricky one but got there , as will you good luck

Used trane's recommended procedure used a refrigerant hose off of the discharge line a sight glass with 1/4 threaded fittings and then hose off of the bottom of oil cooler then moved the sight glass up and down against the oil separator until level could be seen in the sight glass. I dont remember the height measurement but it was taken off of the base rail on the unit support.

The drop across the oil filter's was 25 lbs at 89 degree outside and 268 on the head. As head pressure is lower now that the temp has dropped so has the pressure drop I was averaging about 10-15 lbs at 60 degrees outside last week.

It's starting loaded from time to time more or less based on help from guys here. The problem is making it act up while I'm standing beside it everytime I'm there early in a effort to troubleshoot it the dang thing runs perfect. Let it go overnight below 50 degrees and it may or may not trip the cold weather seems to make this bug surface. When it's 55+ she runs perfect and never acts up we are between cold fronts right now and it's running perfect. No codes when I check it this morning.

Used trane's recommended procedure used a refrigerant hose off of the discharge line a sight glass with 1/4 threaded fittings and then hose off of the bottom of oil cooler then moved the sight glass up and down against the oil separator until level could be seen in the sight glass. I dont remember the height measurement but it was taken off of the base rail on the unit support.